Characteristics of Animals + Sponges & Cnidarians Chapter 23A Honors Biology & Chapter 30 Biology...
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Transcript of Characteristics of Animals + Sponges & Cnidarians Chapter 23A Honors Biology & Chapter 30 Biology...
Characteristics of Animals + Sponges & Cnidarians
Chapter 23AHonors Biology
& Chapter 30 Biology
Jenkins
What is an ANIMAL?
1. Multicellular, eukaryotes
2. Heterotrophs
3. No cell walls, many have specialized functions
4. Usually have a method of movement
5. Most reproduce sexually
6. Requires oxygen
GROUPS
1. Vertebrates = have a backbone
- 5%
2. Invertebrates = have no backbone
- 95%
WHY THE BIG DIFFERENCE?
Survival Needs
• Feeding• Respiration• Circulation• Excretion• Response• Movement• Reproduction
• All animals:– Feed: carnivores, herbivores, omnivores, detritivores
(eat/decompose dead materials), filterfeeders, predator, prey, symbiotic relationships (parasite/host)
– Respiration: take in oxygen give off carbon dioxide
– Circulation: diffusion or system
– Excretion: release ammonia and other waste products
– Response: nerve cells that respond to stimuli
– Movement: ability to move parts or move around
– Reproduce: sexually (egg & sperm) or asexually (budding)
Describe the Body Plans of Animals
1. Symmetry: balance in body proportions
2. Asymmetrical:have irregularly shaped bodies, no symmetry
Spherical Symmetry = globe or ball shaped
Ex. Volvox
Dorsal side
Posterior end
Anterior end
Ventral side
Plane ofsymmetry
Radial SymmetryBilateral Symmetry
Planes ofsymmetry
3. Radial symmetry: can be divided along any plane to produce 2 halves which look
alike (like a pie or bicycle wheel)
4. Bilateral: can be divided only one way to produce mirror image halves
Asymmetry
• Irregular Body Shape
• Often sessile organisms
• Ex. sponges
Radial Symmetry
• Can be divided along any plane, into roughly equal halves.
• Ex. Sea Star
Bilateral Symmetry
• Can be divided into similar left and right halves that form mirror images of each other.
5. TERMS OF DIRECTION:
a. anterior: head regionb. posterior: tail regionc. dorsal: back or topd. ventral: abdomen or bottom
Dorsal
Ventral
AnteriorPosterior
Trends in Evolution• Complex animals have high
level of cell specialization, internal structures, front end/head with sensory organs and a body cavity
1. Cell Specialization = separate roles for each type of cell in multicellular organisms
Cephalization
• Animals with cephalization, have the brain and their sense organs toward the front / anterior aspect of the body
• Allows them to respond quicker
Body Cavity Formation
• Most animals have a body cavity (fluid filled space between digestive tract and wall)
• Important because organs can be suspended in there
• Some cavities contain fluid involved in circulation, feeding and excretion
2. Early states of development -cells divide to produce a hollow ball of cells called blastula.
• SKETCH – From Overhead
Animal Development
• Most develop from a single fertilized egg called a zygote.
• 2 Stages of developmentBlastula- single layer of cells around a fluid-filled space.Gastrula- structure made of two cell layers
Blastula Development
Gastrula Development
Protostome and Deuterostomes
• See page 661 in Dragonfly textbook and sketch it!
Protostome vs Deuterstome
Protostome: (from the Greek: first the mouth)
• An animal whose mouth is formed from the blastopore (opening in the gastrula)
• Most invertebrates
Deuterostome: (from the Greek: "second mouth" )
• An animal whose anus is formed from the blastopore, mouth formed second
• Ex. Echinoderms and all vertebrates
Animation of Protostome & Deuterostome Development
• http://glencoe.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it+swf::550::400::/sites/dl/free/0078695104/383922/ch24.swf::Visualizing Protostome and Deuterostome Development
ENDODERM = innermost germ layer• Becomes: lining of digestive tract and
much of respiratory systemECTODERM = outermost germ layer• Becomes: sense organs, nerve and
outer layer of skinMESODERM = middle germ layer• Becomes: muscles, circulatory system,
reproductive and excretory systems
SpongesPhylum: Porifera
Sponges – Introduction
• Simplest, oldest animal type
• Evolved about 540 million years ago (mya)
• Found in oceans everywhere, and some in freshwater
• Phylum Porifera = “pore bearing”
Characteristics of Sponges• Multicellular, eukaryotic, sessile
(not moving) heterotrophic filter feeders, no cell wall, few specialized cells,
• Asymmetrical, look like large, cylindrical water pump.
• 2 cell layers thick• Choanocytes (collar cells)- move
water through the pore cells into the body cavity and out the osculum
• Simple skeleton made of spicules • Archaeocytes (cells that move
through the sponge distributing food and making spicules)
Section 26-2
Figure 26–8 The Anatomy of a Sponge
See handout given out in class
Feeding in Sponges
• Water flow provides for feeding, respiration, circulation and excretion.
• Sponges filter feed.
• Choanocytes trap food particles as water circulates.
• Food is digested intracellularly.
• Archaeocytes distribute food to other cells.
Sponge Animation
• http://glencoe.mcgraw-hill.com/sites/0078695104/student_view0/unit7/chapter24/concepts_in_motion.html#
Respiration, Excretion & Circulation in Sponges
• Water circulates through sponge.
• Oxygen diffuses out of the water, into cells.
• Carbon dioxide leaves the cells and enters the water.
• Sponges rid wastes by letting it diffuse out.
• Sponges rely on water movement to circulate what they need.
What about a Nervous System?
• Sponges do NOT have one!
• Some can make toxins for keeping predators away!
• Reproduction- sexual or asexual, most are hermaphrodites (produce both egg & sperm at different times)– Sexual- sperm from one sponge are carried to
another sponge for internal fertilization. Larva (immature stage that looks different from the adult) is released and swims away. (Advantage?)
– Asexual- budding or gemmules (a group of archaeocytes surrounded by spicules- can survive harsh conditions until ready to grow
Ecology of Sponges
• Large sponges – provide habitat for marine invertebrates (IE: shrimp, sea stars, snails)
• Some live in symbiosis with Bacteria, Algae and Protists.
• ? Why are some sponges Green?
CNIDARIANSPHYLUM CNIDARIA
CHARACTERISTICS
• 1. Soft-bodied• 2. Carnivores• 3. Have stinging tentacles arranged in
circles around mouth– Used for defense and to capture prey
• 4. Marine (A few Freshwater)• 5. Invertebrate• 6. Radial Symmetry• 7. Simple Nervous system
Nematocysts
• Are poison filled stinging structures.
• Used for defense and to capture prey.
Two Body Forms
• Polyp
• Vase-shaped body
• Medusa
• Bell-shaped body
Other Structures• Nerve net-allows for
detection of stimuli.• Ocelli (eyespots)- detect
light• Hydrostatic skeleton-
enhances movement.• Gastrovascular
cavityinterior cavity where food is digested & nutrients are circulated around the body
Reproduction
• Asexual- budding
• Sexual- external fertilization in water
Class Scyphozoa
• Medusa Stage
• Ex. jellyfish
Class Hydrozoa
• Polyp/Medusa Form
• Ex. Portuguese-Man-Of-War
• Ex. Hydra
Class Anthozoa
• Polyp Stage• Destroyed by human
activity• Ex. Sea Anenome and
Coral
Cnidarian Life Cycle
• http://glencoe.mcgraw-hill.com/sites/0078695104/student_view0/unit7/chapter24/concepts_in_motion.html#